Three cubes of sides 1,2,3 cm are at constant temperature of `100^(@)C`. Then the amount of heat lost per second by them are in the ratio

Options

A. `1:8:27`
B. `27:8:1`
C. `1:4:9`
D. `9:4:1`

Answer

C

Explanation

`R_(1)=sigmaA_(1)T^(4)`
`R_(2)=sigmaA_(2)T^(4)`
`R_(3)=sigmaA_(3)T^(4)`
`R_(1):R_(2):R_(3)=A_(1):A_(2):A_(3)`
`=l_(1)^(2):l_(2)^(2):l_(3)^(2)`
`=1:4:9`